An assembly of mains electricity (AC-powered) devices designed for the continuous and transcutaneous measurement of a patient's blood gas parameters, typically blood partial pressure of oxygen (pO2), blood partial pressure of carbon dioxide (pCO2), haemoglobin oxygen saturation (SpO2), and/or venous blood oxygenation through the jugular vein (SjvO2); often with pulse rate. It consists primarily of a probe for gas detection (e.g., via transcutaneous gas diffusion, or using light spectroscopy) placed on the patient’s skin, and an oximetry monitor for the measurement, analysis, and display of data; patient adhesives and connecting cables may be included.